Whiffs of chemicals found in rocket fuel, a dark pyramid that resembles rare volcanic rocks on Earth and glassy particles bearing traces of water are among the Curiosity rover’s finds in its first chemical investigation of Martian dirt.

“This is the first time we’ve known precisely and definitively what this stuff is made of,” says astrobiologist David Blake of the NASA Ames Research Center in Moffett Field, Calif. He and his colleagues report the results of the analysis September 26 in Science.

In samples scooped from Martian dust, Blake and his colleagues found a mix of crystals from volcanic rocks plus glassy particles. Researchers discovered the blend by bombarding soil with radioactive alpha particles and using the energy signatures bounced back to identify the soil’s chemical contents.